Protective device



lJan. 15, 1924.

1,481,005 G. B. PHILLIPS PROTECTIVE DEVICE Filed June 18, 1918 INSULATION INSULATION George B Phillips, b5 Mfr F/f/v His Aller-hei J Patented Jan. l5, 1924.

Y lar in Configuration.

UNITED STATES GEORGE B. PHILLIPS, OF SCHENECTADY,

'ro ammi. um.

TRIO COHPNY, A CORPORATION OF NEW YORK.

PROTECTIVE Davia-Is.

Application led June 18, 1918. Serial No. 240,064.

To all whom it mag/concern:

Be it known that I, GEORGE B. PHILLIPs, a citizen of the United States, residing at Schenectad in the county of Schenectady, State of Niiw York, have invented certain new and useful Improvements in Protective Devices, of which the following is a speciication.

My invention relates to protective devices and more particularly to llghtning arresters and has for its object to provide a lightning arrester of the vacuum type in which discharges are prevented from'fiashing over the electrodes, in which the spark gap cannot be short-circuited, in which the atmoshere within the arrester is not impaired y repeated discharges, and which is in general an improvement over similar devices heretofore known in the art.

The novel features which I believe to be characteristic of my invention will be defined in the claims appended hereto, while the features of construction and mode of operation will be understood by reference to the following description taken in connection with the accompanying drawing, in which: p

Fig. 1 is a side elevation, partly in section, of a protective device of the vacuum arrester type embodying the novel features of my intention, and Figs. 2 and 3 are sectionai fe of a' portion of the device i 1, showing modifications of my invention.

The prete-@tive device, as shown in Fig. 1, comprises an evacuated vessel or container 1, contairs-11,52 an atmosphere of a monatomic gas, preferably argon, and, in the construction shown, the vessel 1 is of glass and tubu- Extending through suitable seals 2 and 3, which are similar in construction to those used in incandescent lamps, are .eading-in wires or conductors 4 and 5 respectively which are preferably of the well known Dumet wire. I have shown the seals and conductors 4 and 'extending into the vessel 1 from opposite ends there# of, but it is understood that this construction is not essential. Mounted or supported upon each conductor 4 and 5 are electrode members 6 and 7 spaced apart to form a spark' gap 8 therebetween and of a configuration to form a protected gap in a substantially uniform dielectric field. Electrodes 6 and 7, preferably, have proximal surfaces which are substantially spherical and one electrode,rfor instance, electrode 7, is of a shape to surround *or enclose the other electrodev 6 or a portion of said electrode, the electrodes being concentrically disposed within the vessel 1. In the construction shown in the drawin this electrode relation is obtained by brming the outer or surrounding 'electrode as a cupshaped member and, as shown, this cupshaped electrode 7 is horizontally disposed within the vessel equidistantfrom the walls thereof and secured to the conductor 5 through an offset ortion 9. The innerelectrode 6 may be sp erical, but I prefer a c lindrical configuration with rounded en s. This electrode 6 extends into the enclosure formed by the cup-shaped electrode 7 but is spaced away therefrom so that all points between said cup-shaped electrode and the enclosed portion of said inner electrode are substantially equidistant. In this manner a substantially uniform dielectric field is provided for'the spark gap 8. The cupshaped electrode 7 also serves the pur se of 'protecting the gap 8 and also the wal s of the vessel 1 from the effects of spark discharges.

As a means for connecting the electrodos between a conductor or line l0 to be protected and ground, conductin or cap meIII-r bers 11 and 12 are rovide surrounding the ends of the vesse 1 and in conducting relation with conductors 4 and. 5 respective `take place from the outer electrode 7 to the inner electrode 6.

To prevent heavy dischargesv or discharges of a continuous character from causing a short circuit of the p due to partial fusion of the electrodes g; the heat of discharge, one or both of the electrodes, but essentially the'inner electrode 6, is made of non-short circuit-forming material, bv which term, I not cause a short-circuit of the spark gap. For such a material, I prefer to use carbon or graphite. In the structure shown,- the outer electrode 7 is of metal such as brass. Y It has been found that discharges between electrodes in a vacuum, often Hash mean a material which willl plied to the unenclosed over the electrodes, such flash-overs taking place to the leading-in wires or conductors d and 5 and particularly over the ground electrode 6 to conductor 4, burning t e conductor away, affecting the walls of the vessel i and causing damage to the seal 2. confine the discharge to the gap 8 and prevent the discharge from flashing over this electrode, by insulating means which protects or encloses the conductors 4 and 5. For this insulating means I, preferably, provide extended or elongated seals 2 and 2% so that the conductors are enclosed therein. To particularly prevent discharges Jrlrom electrode 7, from flashing over electrode 6 to conductor 4, I countersink the tip of seal 2 in the end ot the electrode so that the junction between this seal 2 and electrode 6 is protected. Ix also provide a {lash-over protector or barrier 13 which, in the form shown in Fig. 1, is a cup-shaped member surrounding the unenclosed or outer portion of the graphite or ground electrode 6. In Fig. 2, the protector 1s in the form o't a disc member llt between the elctrode 6 and seal 2 having portions thereof extending into the path of the dash-over. 'Ihe central part ot member 14 has an extension countersunk in the end of electrode 6 to suitably protect the junction between the disk 1i and the electrode. lin iiig. 3 a further modified torni ot flash-over protector is provided, consisting ot an insulating coating 15 which may be painted or otherwise apportion ot the electrode tl.

It is a well hnown 'tact that the electric discharge between electrodes in an attenuated gas alter the pressure ot gas by two phonomena going on at the saine time, namely, removal of gas by the so-called clean-up eiciect and the evolution ot gas trom the electrodes due'to the discharge. rihe resulting changes ot pressure and composition ot the gas within the vessel affects the voltage value at which a discharge will occur. li overcome these disadvantages by a treatment or the electrodes which consists in heating them to ahigh temperature in a suitable receptacle, exhausting the air there from and then permitting the electrodes to cool in an atmosphere of lthe monatomic gas with which the vessel is to be illed. In this manner the electrodes in cooling absorb the monatomic gas and when such eiectrodes are repeatedly heated by spark discharge within the evacuated vessel 1 and cooled, a minimum effect is observed upon the pressure or the atmosphere within the vessel 1 and no deleterious gases are given oli:` and hence a more uniform arc-over potential can be obtained.

In accordance with the provisions of the patent statutes, I have described the principle oit operation ot my invention7 together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the ap-l paratus shown is only illustrative and that the invention can be carried out by other means. .r

What I claim as new and desire to secure by Letters Patentv of the United States, is

1. In combination with a line to be protected, a protective device connected in circuit between" said line and ground comprising an evacuated vessel, a cup-shaped electrode connected to the positive side of said circuit, and a cooperating electrode extend ing within the enclosure of said cup-shaped electrode and adapted to be connected to the negative side of said circuit, said electrodes being separated to form a spark gap.

2. A protective device comprising an evacuated vessel, a cup-shaped electrode within said vessel, and a cooperating electrode within the enclosure of said cup-shaped electrode and separated substantially' equidistant therefrom to form a spark gap, said electrodes being connected in such a relation that a discharge takes place from said cupshaped electrode to said cooperating electrede 3. A protective device comprising an evacuated vessel, two cooperating electrodes within said vessel, one surrounding the other and spaced apart to form an enclosed sparlr gap therebetween, at least one ot said electrodes being ot carbon tree 'from deleterious gases,

d, l-l protective device comprising an evacuated vessel, two cooperating electrodes within said vessel, one electrode enclosing the other to provide a spark gap there between, conductors secured to said electrodes, insulating means surrounding one ot said conductors and means between said insulating means and the corresponding elecm trede tor preventing discharges across said gap from tlashing over to said one conductor- 5.. .d protective device comprising an evacuated vessel, two cooperating electrodes within said vessel concentrically arranged and spaced apart to torni a spark a protecting member adjacent the inner elec trede in position to prevent discharges across said gap :trom dashing over said inner electrede..

6. A protective device comprisn an evac uated vessel, two cooperating elec redes within said vessel spaced. apart 'to '.orin a spark gap, conductors secured to said electrodes, insulating means enclosing said confs ductors and a barrier adjacent one oit said electrodes in position to across said gap from dashing over said elec trede t?, it. protective device comprising an evacuated vessel, conductors extending into said vessel, seals tor said vessel completely enprevent discharges l Oap, and

closing said conductors, and cooperating electrodes carried by said conductors adjacent said seals and separated to form a spark gap, the end of one of said seals being countersunk in its adjacent electrode.

8. A protective device comprising an evacuated vessel containing an atmosphere of a monatomic gas, electrodes within said vessel cooperating toform a spark gap, said electrodes containing said monatomic gas and being free from deleterious occluded gases whereby they are ca able of operating upon spark discharge wit out impairing the atmosphere within said vessel and with a minlmuin effect upon the pressure therein.

9. The method of treating electrodes L forming a spark gap in 'an evacuated v containlng monatomic gas, which consists in heatingsaid electrodes to a high temperature in a receptacle, exhausting the air from said receptacle and permitting said electrodes to cool in an atmosphere of the monatomic gas.

In witness whereof, I have hereunto set -my hand this 17th day of June, 1918.

GEORGE B. PHiLLIPs. 

